How Long Does Aimovig (Erenumab) Take to Work?

How Long Does Erenumab Actually Take to Work?

Aimovig is a once‑monthly injection that helps prevent migraine attacks before they start. It works by blocking CGRP, a nerve signal involved in triggering migraine pain.

If you just started Aimovig and are wondering when your migraines will be relieved, most people see a meaningful reduction in migraine days within 1 to 3 months. Some notice improvement as early as the first week. That is faster than many older preventive medications, but it is still not instant, and knowing that upfront makes the waiting period much easier to manage.

Clinical trials called STRIVE and ARISE showed statistically significant migraine reduction by month 1 at the 70 mg dose. Researchers typically define a "meaningful response" as a 50% or greater drop in monthly migraine days. Keeping that benchmark in mind helps you set realistic expectations rather than judging the medication too soon.

What Does the First Month on Erenumab Look Like?

The first injection starts blocking CGRP receptors (proteins in the nervous system that play a central role in migraine pain signaling). Full steady-state levels build up over successive monthly doses, so month 1 is really about establishing a foundation.

Here is what many patients experience early on:

• Some early relief: A portion of people notice fewer or less severe migraines within the first 2 weeks, though this is not guaranteed.
• Fluctuation before stability: Migraine frequency may vary in month 1 before settling into a clearer pattern.
• No instant rescue effect: Erenumab does not stop a migraine already in progress. It is prevention only.

Keeping a headache diary starting on day one is one of the most clinically useful things you can do. It turns vague impressions into real data your doctor can act on.

70 mg vs. 140 mg: Does the Higher Dose Work Faster?

Both doses showed benefit by week 4 in the STRIVE trial, so the starting dose does not dramatically change how quickly you feel results. The difference lies in how much benefit you get, not when it begins.

The 140 mg dose produced a larger proportion of 50% responders overall. Many physicians start patients at 70 mg and escalate to 140 mg after about 3 months if the response is not sufficient, rather than switching to a different medication right away. That stepwise approach is practical and avoids unnecessary treatment changes.

Is Erenumab Working, or Should You Make a Change?

Patients are advised to use the medication for at least 3 months, and ideally 6, before concluding it is not working. American Headache Society guidance supports that window specifically because partial responders at month 3 often continue improving through month 6.

One hidden factor that can make erenumab look like it is failing: medication overuse. Using acute pain relievers (like triptans, NSAIDs, or combination headache tablets) more than 10 days per month can blunt erenumab's effect and mimic non-response. If you are in that pattern, addressing it is essential.

Signs that suggest erenumab may genuinely not be the right fit after a full trial:

• No change in migraine frequency after 6 months at the 140 mg dose
• Persistent side effects such as constipation or injection-site reactions affecting daily life
• Migraine severity worsening rather than holding steady or improving

Erenumab is a genuinely useful advance in migraine prevention, but some expectations may noy ne valid.

• It is not for active attacks. If you have a migraine right now, erenumab will not help. You still need a separate acute treatment plan.
• Not everyone responds. Roughly 20 to 30% of patients do not reach the 50% responder threshold even after a complete trial. That is not a personal failure; it reflects biological variability in how people respond to CGRP blockade.
• Higher cost does not mean faster onset. Erenumab costs significantly more than oral preventives like topiramate or amitriptyline. The advantage it offers is better tolerability and once-monthly dosing, not a quicker start. For patients who tolerated older medications well, the cost difference may not be justified by speed alone.

A follow-up appointment at the 3-month mark is standard practice for reviewing your monthly migraine day count against your baseline. Come prepared with your headache diary so the conversation is based on data, not memory.

Reach out sooner if you notice:

• No reduction in migraine frequency after 3 full months of treatment
• New or worsening constipation, which is the most commonly reported side effect
• Injection-site reactions that are not improving
• A sudden increase in migraine severity rather than gradual improvement

The MIDAS (Migraine Disability Assessment) score is a short validated questionnaire that helps you and your provider measure how much migraines are affecting your work, household activities, and social life. Scoring yourself before and after 3 months gives a structured, objective picture of whether things are genuinely moving in the right direction. Doctronic, the first AI legally authorized to practice medicine, offers 24/7 HIPAA-compliant consultations so you can get guidance on your erenumab progress without waiting for your next scheduled visit.

Frequently Asked Questions

Can erenumab work after just one injection?

Yes, some patients report fewer or less severe migraines within the first two weeks after their first injection. However, this is not universal, and one injection typically establishes only initial CGRP receptor blockade, not full steady-state effect.

What should I do if Aimovig is not working after 3 months?

Talk to your doctor before stopping. Your provider may recommend escalating from 70 mg to 140 mg, checking for medication overuse, or extending the trial to 6 months, since partial responders often continue improving through month 6.

Does erenumab get more effective over time?

For many patients, yes. Clinical trial data shows the proportion of people reaching significant migraine reduction tends to grow from month 1 through month 6 as the drug reaches steady-state levels with each successive monthly injection.

How do I know if erenumab is working if my migraines are irregular?

A validated tool like the MIDAS (Migraine Disability Assessment) score can help quantify change beyond just counting days. Tracking patterns in a headache diary for at least 3 months gives a clearer picture than memory alone.

Can you speed up how fast erenumab works by taking a higher dose sooner?

Not meaningfully. Both the 70 mg and 140 mg doses show similar onset timing in clinical trials. The higher dose may produce a larger overall response, but starting at 140 mg does not appear to accelerate when the benefit begins.

The Bottom Line

Patience through the 3-to-6-month window is the single most important factor in giving erenumab a fair chance. Some patients notice early wins within the first two weeks, but clinical trials show that the proportion of people reaching meaningful migraine reduction keeps growing through month 6. A partial response early on is often a promising sign worth continuing rather than a reason to switch. If you are unsure whether your progress is on track, Doctronic offers free AI consultations and $39 video visits, available 24/7, giving you accessible expert guidance anytime. With over 22 million AI consultations completed and 99.2% treatment plan alignment with board-certified physicians, Doctronic can help you and your provider make smarter decisions about your migraine care. This article is informational and is not a medical diagnosis. Confirm with a licensed clinician, especially for new, worsening, or high-risk symptoms.